I believe some years ago I wrote about working on the mortise lock
on my front door. I did some things to it, removed some parts for
features not needed (all I want is the doorknob mechanism, I lock
the door with a separate deadbolt) and put it all back together.
Things worked okay after that. A couple of years after that fix I
made a metal plate to reenforce the door where the front pull and
thumb latch attach. Too many years of taking the parts off and
putting them on (and several different ones with slighty different
mounting screw locations) had taken their toll. I got a large brass
push plate and drilled holes everywhere I needed (some small for
the screws, some large for the lock cylinder and door latch). If
I didn't post about that work here, I posted about it in
rec.crafts.metalworking.
(Let me say if you are looking for life on Usenet, r.c.m is very
lively, although about half the content is off-topic. It's a good
place to talk about any metalworking, even stuff like soldering,
and many other things involving metal like tools.)
Well lately it hasn't been working right again. The thumb latch
increasingly wasn't operating the spring bolt, and then on the
inside the doorknob came off.
Well, fixing the doorknob was easy. The metal is getting old
and worn for the knob key attachment. But rotate it ninety
degrees and there's a fresh bit not worn.
However while working on that I noticed something. The front
thumb latch works reliably and doesn't work at all depending
on how far the doorknob is turned.
AHA!
That's my key to understanding why the thumb latch doesn't work.
There must be a problem with the spring that pushes the latch
bolt out and thus positions the doorknob. So I took the whole
thing apart and looked at the spring. It was about an inch long,
wrapped around a metal bar coming out of the latch. It looks like
it should be about an inch and a quarter or an inch and a half.
There's no way to replace it without threading it off and threading
a new one on. It comes back to me that I didn't replace the spring
last time because of that problem and just assembled it as is
because I didn't realize the importance of a full size spring.
One trip down to my local hardware store (my local hardware store
is the sort where the staff actually knows stuff, it costs more
but it's convient and good to support places that hire knowledgable
people). I show a guy the lock and ask what spring I can get. He
fiddles around in a drawer and comes back with a spring the right
diameter but two inches long. He asks me if I can cut it to size,
and I say I can, so he says it's a buck for the spring.
I take it home, unthread the old spring, cut the new one large
and thread it on. Then I trim little bits off until the tension
feels right. Reassemble the lock, reassemble the latch in the
door, test it. Works great, like new.
Oh, and a little tidbit my wife just did:
http://www.sonyaphilip.com/waw/2011/03/reinventing_the_wheel.html
Elijah
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took the spokes out of the wheel for her
